In accordance with the modern digital era and present need for fast and efficient means of relaying information, the telecommunications industry has provided many significant technological advancements. Currently, many residential and commercial locations worldwide utilize some sort of high-speed data network for transmitting and receiving different types of digital information. For example, many homes today often employ a high-speed cable modem or digital subscriber line (DSL) link for connecting to the internet, receiving cable television service, and/or implementing other communication applications that employ digital signal configurations.
Given the more prevalent availability of such high-speed data networks at residential and commercial locations, VoIP technology has been developed to apply the benefits of high-speed digital data transfer to existing telephony applications. Current communication via telephone networks employs analog signal transmission, and thus conversion from analog to digital communication offers many potential benefits including increased signal clarity and reduced signal interference.
In order to utilize high-speed data networks for voice receipt and transmission, hardware must be provided at each end location to implement analog-to-digital (A/D) and digital-to-analog (D/A) signal conversion. By providing such conversion hardware, signals can be transmitted from a cable modem termination system (CMTS) or other front end of a network service provider to various end locations. Once digital signals are received at each end location, D/A conversion enables a user to hear the analog voice signal at a telephone handset. Similarly, an analog voice signal provided by a user can be converted to a digital signal at the end location and then transmitted digitally over the high-speed data network to a desired destination.
For high-speed cable networks, the hardware required at each end location typically includes at least a cable modem and appropriate signal interface. For such high-speed networks that also provide VoIP capabilities, additional hardware must be provided in a specialized cable modem, such as a Touchstone brand telephony modem as offered for sale by Arris Corp. Such VoIP cable modems may be provided as a “black box” type structure on the outside of a house or other end location. Conventional VoIP cable modem embodiments preferably include a central processing unit (CPU) with various hardware and software components, a digital signal processor (DSP), and a line card with A/D and D/A conversion functionality.
Certain performance characteristics such as speed, efficiency, and signal quality are inherently part of preferred modem design criteria. As a result, signal routing among the components of a VoIP cable modem or other high-speed data interface is critical to the performance of VoIP applications. In conventional VoIP cable modem embodiments, data packets received by the CPU from a high-speed transmission medium are sorted and routed via software to the DSP component. However, implementation of software routing protocols often requires a significant amount of valuable CPU clock cycle time as well as CPU power. Thus, improvements in signal routing within cable modems having VoIP telephony functionality are highly desirable.